High-performance computing systems often include large numbers of servers interconnected by a network switch fabric that is responsible for communicating packets to and from the servers. Each of these servers can potentially run multiple virtual machines (VMs) and associated virtualized applications, and the network packet streams generated by these servers are typically directed to different resources that the VMs and associated virtualized applications need to access. Hot spots and associated network congestion frequently arise in such network switch fabrics depending on the patterns of the packet streams and how the switch fabric is configured.
In an exemplary configuration, a high-performance Infiniband™ network switch fabric can be used to connect a large number of servers with an Ethernet™ gateway. In this configuration, traffic through the Ethernet gateway comprises virtualized traffic streams associated with VMs that execute on various servers in the data center. In general, traffic streams to and from the VMs have stringent requirements for traffic isolation and independent policy enforcement. For example, some of these policies could be related to traffic management, firewalls, and L3-L7 packet-processing.
In a network switch fabric, hot spots frequently arise at points in the network hierarchy where traffic from multiple sources tends to aggregate. For example, a virtual switch (vSwitch) uplink node aggregates traffic from multiple VMs, a NIC port aggregates traffic from multiple vSwitches, a network tier uplink node aggregates traffic from multiple NIC ports, and so on. These hot spots can adversely affect the performance of the VMs and virtualized applications running in the network hierarchy.
Hence, what is needed is a technique for managing hot spots and associated network congestion in a network switch fabric.